Fluid flow control valve

ABSTRACT

A flow control valve is disclosed comprising a valve housing defining a through flow passage, a valve member supported in the housing for pivotal movement with respect to the housing between an open position in which flow through the passage is enabled and a closed position wherein flow through the passage is blocked, and an actuator for moving the valve member between said position. A linkage transmits actuating force from the actuator to the valve member and, a force limiting device limits the actuating force transmitted to the valve member when the valve member is in its closed position.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to valves and more particularly relates tobutterfly type valves operated between open and closed positions byactuators.

2. Prior Art

So-called butterfly type valves have long been used for controlling theflow of various kinds of fluids in many different applications. Onerelatively common area of usage of such valves is in automotive vehiclesdriven by liquid cooled internal combustion engines and in whichbutterfly valves have been used to govern the flow of engine coolantthrough heat exchangers known as "heater cores" which function to heatair circulated in the vehicle passenger compartments. In this and othergenerally similar applications it is essential that the butterfly valvefunction to effectively seal against passage of fluid when in its closedposition. Accordingly, many prior art butterfly valve constructions haveemployed a butterfly valve member positioned in a valve housing definingthrough flow passage for the fluid with the butterfly valve having aresilient periphery sealingly engageable with the surrounding valvehousing wall when the valve member is in its closed position.

In many applications the butterfly valves are opened and closed inresponse to a remotely sensed condition such as air and/or liquidtemperature, and in such circumstances it is common to provide anactuator of some sort for shifting the valve member between open andclosed positions in response to changes in the sensed condition.Examples of valves constructed in this general fashion are illustratedby U.S. Pat. Nos. 3,857,406; 3,568,975; 3,675,681; 2,544,520; and4,176,823.

In the butterfly valve assemblies illustrated by the U.S. Patentsreferred to above, the butterfly valve is operated between its open andclosed positions by a fluid pressure operated actuator. In thedisclosures of these patents the actuator is operated by differentialair pressure applied to a piston or diaphragm which is in turn connectedto the butterfly valve by a force transmitting linkage. The piston ordiaphragm is also acted upon by a spring which actuates the valve to itsopen position in the absence of a differential pressure force acting onthe piston or diaphragm.

In automotive vehicle applications it is commonplace to utilize thevacuum pressure in the engine intake manifold as a source of operatingpressure for valve actuators of the type referred to. When one side ofthe piston or diaphragm is communicated with the engine intake manifoldwhile the opposite side is exposed to atmospheric air pressure, theresultant differential air pressure acting on the piston or diaphragmmoves the piston or diaphragm against the force of the spring and shiftsthe valve member to its closed position. The degree of vacuum pressurepresent in the engine intake manifold thus determines the magnitude ofthe valve closing force. This vacuum pressure varies widely dependingupon operating conditions of the engine. Thus it is necessary to designthe actuator so that the valve can be tightly closed against fluid floweven when the engine intake manifold vacuum is quite small (i.e. closeto atmospheric pressure). As a result, when engine manifold vacuumlevels are high, the valve actuators are capable of exerting asubstantial excess amount of closing force on the already closed valve.

Excessive valve closing forces have led to failures of otherwise wellconstructed, functional valves. When a valve is in its closed conditionand the engine is operated under various load and speed conditions, theclosed valve is, in effect, cranked by varying forces while in itsclosed position and when the valve member is formed with a resilientlydeformable periphery for sealing purposes, the valve tends to becomejammed in its closed position. The cyclical cranking forces also tend tocause spalling of the resilient valve members which results in the valvemembers eventually failing to seal against the valve housing when intheir closed positions.

Moreover, many valves of the type referred to have to be constructed bypositioning the butterfly valve member within a surrounding valve bodyand then fixing the valve member to its operating shaft. Fixing thevalve member to its shaft in situ is sometimes accomplished by spotwelding and sometimes by cold forming a driving connection between theshaft and valve. Examples of these assembly techniques are disclosed,respectively, by U.S. Pat. Nos. 3,568,975 and 4,176,823. These kinds offorce transmitting connections between valve member and shaft areadequately strong to assure opening and closing of the valves but havenot always had sufficient strength to resist excessive valve closingforces without breaking.

In many valves the driving connection between the actuator linkage andthe valve member shaft is also a relatively light duty connection whichcan be rendered ineffective by the application of excessive valveclosing forces. It has become a common practice, particularly in theautomotive industry, to test the valves by applying closing forcessubstantially greater than those expected to be encountered during useto determine whether the valves jam or the driving connections fail.Such testing results in the failure of many valves which are otherwisereadily capable of operating satisfactorily in the absence of excessiveclosing forces.

SUMMARY OF THE INVENTION

The present invention provides a new and improved flow control valvehaving a valve housing defining a fluid flow passage with a valve membersupported by the housing for rotation between an open position whereinfluid flows through the passage and a closed position wherein thepassage is blocked. An actuator moves the valve member between itspositions with the actuating forces transmitted to the valve member viaa linkage arrangement. A force limiting device prevents transmission ofexcessive actuating forces to the valve member when in its closedposition.

In one preferred form of the invention a liquid flow controlling valveis provided which includes a tubular valve housing defining a fluid flowpassageway, a valve member supported in the housing for pivotal movementbetween open and closed positions with the valve member sealinglyengaging the valve housing when in a closed position and a valveactuator including an actuator housing and a movable actuator member. Astructural support housing interconnects the actuator housing and thevalve housing for preventing relative movement between them, and anactuating force transmitting linkage is disposed between the pressureactuated member and the valve member for moving the valve member betweenits positions. The force limiting device is formed by an abutmentelement associated with the linkage which is engageable with one of thehousings to limit the force applied to the valve member when the valvemember is in its closed position.

In a preferred and illustrated valve embodying the invention theabutment element projects from the linkage for engagement with thesupport housing so that the force applied to driving connections betweenthe linkage and the valve member and its supporting shaft is limited.

Other features and advantages of the invention will become apparent fromthe following detailed description of a preferred embodiment made withreference to the accompanying drawings which form a part of thespecification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a control valve embodying the presentinvention with portions broken away and shown in cross section;

FIG. 2 is a view seen approximately from the plane indicated by the line2--2 of FIG. 1 with portions broken away and shown in cross section;and,

FIG. 3 is a view seen approximately from the plane indicated by the line3--3 of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENTS

A flow control valve 10 embodying the present invention is illustratedin the drawings. The preferred and illustrated flow control valve 10 isconstructed and arranged for controlling the flow of internal combustionengine coolant to a heater core (not illustrated) in an automotivevehicle. The valve 10 includes a valve housing 12 defining a throughpassageway for engine coolant, a valve member 14 disposed within thehousing 12 for governing the flow of coolant through the passageway, anactuator 16 for operating the valve member between open and closedpositions through the agency of a linkage 18, a support housing 20 forsecuring the actuator 16 and valve housing 12 in a predetermined fixedrelationship with respect to each other, and a force limiting device 22for preventing transmission of excessive closing forces to the valvemember.

The valve housing 12 is constructed to be connected in the enginecoolant system. The preferred housing 12 is formed by a pair of tubularhousing members 30, 32 which are secured together to define the flowpassage, which is indicated by the reference character 34. The housingmember 32 defines an enlarged passage section 36 (FIG. 2) within whichthe valve member 14 is received and the housing members 30, 32 aresecured together along confronting radially outwardly extending flanges38, 40. The interface of the flanges is sealed by a sealing ring 42interposed between them. The housing members 30, 32 define respectiveoppositely extending hose nipples 44, 46 shaped to sealingly receive theusual engine coolant hoses by which the engine coolant is directedthrough the valve housing. The housing members 30, 32 are illustrated asformed of molded plastic material but it should be appreciated thatthose members could alternatively be formed by die cast aluminum partsor from other suitable materials.

The valve member 14 is pivotally supported in the enlarged passagesection 36 for movement between an open position and wherein enginecoolant is permiteed to flow through the housing 12 and a closedposition in which the engine coolant flow through the housing 12 isblocked. In the preferred and illustrated embodiment the valve member 14is fixedly connected to a driving shaft 48 which extends through thepassage section 36 and is supported by opposed bearing portions 50formed integrally with the housing member 32. The valving member 14 ispreferably of generally elliptical configuration (see FIG. 1) and, asbest illustrated by FIG. 2, is formed by an assembly of a metal centralsupport member 52 drivingly connected to the shaft 48, a resilientlydeformable rubber-like valve body 54 carried on the member 52, andsupporting plates 56 disposed along opposite faces of the valve body 54.The body 54 defines a resiliently deformable valve body periphery 58which, when the valve member is in its closed position, sealinglyengages the surrounding cylindrical wall of the housing member 32 sothat coolant is prevented from flowing the housing 12 around theperiphery of the valve member. The valve member is of the sort generallyreferred to as a "butterfly" valve and the preferred construction of thevalve member is shown and described in detail in U.S. Pat. No. 4,176,823the disclosure of which is incorporated herein by this reference to it.

Because the housing member 32 is tubular and continuous, the valvemember 14 must be positioned within the body member 32 before it isassembled to its driving shaft 48. In the illustrated valve the shaft isformed with a splined central section which is press fit into anundersized hole in the central support member 52 so that the supportmember material is cold formed into a driving connection with the teethof the shaft splines (see FIG. 2). Other forms of driving connection canbe employed, such as spot welding, if desirable and convenient.

The actuator 16 moves the valve member 14 between its open and closedpositions to control the flow of coolant through the valve housing. Thepreferred actuator is formed by an actuator housing 62, a pressureresponsive actuator member 64 movable relative to the housing 62, and anactuating spring 66 which reacts between the housing 62 and the actuatormember 64. The actuator housing 62 is preferably formed by a moldedplastic cup having a port 68 projecting from its closed end and anenlarged lip 69 extending about its open end.

The actuator member 64 is formed by a disphragm 70 and a reinforcing cup72 carried by the diaphragm. The actuator member is hermetically sealedin place across the open end of the housing 62 with the diaphragm 70forming an external peripheral sealing lip 74 which is sealingly engagedwith the housing cup lip 69. The diaphragm itself is formed by a thinflexible membrane of rubber-like material defining a central opening inwhich a central projecting part of the diaphragm reinforcing cup 72 issealingly retained.

The actuating spring 66 is preferably a helical compression spring whichis compressed between the closed end of the actuator housing cup 62 andthe closed end of the diaphragm reinforcing cup 72. In the absence ofdifferential pressure exerted upon the diaphragm 70, the spring 66 urgesthe actuator member 62 in a direction outwardly relative to the open endof the actuator housing cup, moving the valve member 14 to its openposition. The spring 66 is preferably received in the diaphragmreinforcing cup 72 so that it does not act directly on the diaphragm.

The pressure within the chamber defined by the actuator housing 62 andthe actuator member 64 is governed by a three-way control valve 80 whichalternatively communicates the chamber to the vacuum pressure in theengine intake manifold or to atmospheric pressure. When the chamber iscommunicated to the intake manifold vacuum pressure, the pressureresponsive actuator member 64 is shifted against the force of the spring66 toward the closed end of the actuator housing 62 as a result of theatmospheric air pressure acting on the external area of the actuatormember 64 and overcoming the force of the spring 66. When the valve 80vents the chamber to atmospheric pressure the spring 66 returns theactuator member 64 toward the open end of the housing 62 sincedifferential pressure forces acting on the actuator member 64 areeliminated. The valve 80 is schematically illustrated and may be of anysuitable construction permitting operation by remotely sensedconditions, or manually, depending upon the circumstances of applicationof the flow control valve 10.

The linkage 18 transmits valve operating forces from the actuator 16 tothe valve member 14. In the preferred embodiment of the invention thelinkage 18 is formed by an operating rod 80 connected to the actuator60, a crank 82 drivingly connected to the valve supporting shaft 48, anda bearing pin 84 rotatably connecting the operating rod 80 to the crank82.

The illustrated operating rod 80 is formed by a sheet metal stamping andhas a tab 86 formed at one end in which an opening 88 is defined forloosely receiving an upset button-like construction 89 on the projectingend of the diaphragm reinforcing cup 72. The construction 89 is roundedso that a limited amount of universal motion is enabled between the rodend tab 86 and the actuator. The oppositely projecting rod end portion90 defines an opening for receiving the bearing pin 84 and is bent tolie in the plane of the center line of the tank opening 88 and the endportion 90. The central body portion of the rod 80 is formed by spacedlegs 92 and a tang 94 which extends between and generally parallel tothe legs 92.

The illustrated crank 82 is formed from sheet metal, has one endconnected to the rod end portion 90 by the bearing pin 82 and itsopposite end 96 drivingly connected to the valve operating shaft. In thepreferred embodiment, the crank end 96 is formed by a return bent endportion 98 which defines aligned openings through which a largerdiameter splined projecting end of the valve shaft 48 is driven toproduce a cold formed driving connection between the shaft and crank.The crank transmits driving rotational force to the valve shaft 48 andthe valve member. The crank is formed with flanges extending along itssides to stiffen the crank against twisting when transmitting torque tothe valve.

The support housing 20 rigidly connects the valve housing 12 andactuator housing 62 together to prevent relative movement between them.Referring to FIG. 3, the support housing 20 is formed by a planar sheetmetal body plate 100 which defines first and second semicircular lobes102, 104 engaging the valve housing and actuator housing, respectively.The valve housing extends through a central opening in the lobe 102 withthe valve housing flange 38 engaging the plate portion 100 about theboundaries of the central opening. The valve housing flanges 38, 40 arerigidly gripped in place against the housing plate portion 100 byfinger-like clinch tabs 108 formed integrally with the plate portion100. A peripheral stiffening flange 110 formed about the outer peripheryof the lobe 102 extends about the valve housing 12 to the juncture ofthe lobes 102, 104 and rigidifies the plate portion 100.

The lobe 104 overlies the open side of the actuator cup 62 and defines aperipheral flange portion 112 which extends around the actuator cup lip69. Spaced fingers 113 extend below the lip 62 to clinch the plateportion 100 of the lobe 104 tightly against the upper side of theactuator cup. The plate portion 100 firmly engages the outer peripheryof the diaphragm 70, urging it into sealing engagement with the housingcup lip. The peripheral flange portion 112 of the lobe 104 thusmaintains the cup, diaphragm, and the plate 100 firmly assembledtogether as well as stiffening the lobe 104. A central opening 114 isformed in the lobe 104 to permit the operating rod 80 to reciprocatefreely through the plane of the plate 100 as the diaphragm 70 is shiftedwith respect to the actuator housing 62.

The force limiting device 22 if effective to limit the magnitude of thevalve closing force transmitted to the valve member 14 when in itsclosed position. In the preferred and illustrated embodiment of theinvention the force limiting device includes an abutment element carriedby the linkage 18 for engaging a surface on one of the housings forlimiting the actuating force transmitted to the valve member. Moreparticularly, the abutment element is formed by bending the tang 94 toproject transversely with respect to the extent of the operating rod 80so that the tang engages the housing plate 100 when the actuator 16 hasmoved the valve member to its closed position. When the abutment elementformed by the tang 94 engages the plate 100 the closing force applied tothe valve member 14 is effectively limited in that the abutment elementlimits further movement of the rod 80. Moreover, because the abutmentelement acts between the rod 80 and the support housing 20 the drivingforces transmitted by the driving connection between the crank 82 andthe valve shaft 48 are limited as are the driving forces between theshaft 48 and the valve member 14. Accordingly the possibility of damageto these driving connections as a result of excessive actuator forces issubstantially reduced.

It should be appreciated that the valve member 14, the shaft 48 and thecrank 82 are assembled in a predetermined angular relationship withrespect to the valve housing 12. Since the valve housing 12 and actuator16 bear a predetermined fixed positional relationship with respect toeach other by virtue of their assembly to the support housing 20, thetang 94 can be bent to form the abutment element prior to final assemblyof the valve member. In the preferred form of the invention the tang 94is bent so that the valve member 14 is moved to its closed position anda slight amount of overtravel of the crank 82 can occur before theabutment element engages the support housing plate 100 to preventtransmission of greater valve closing force. This assures that the valvemember sealingly engages the valve housing yet minimizes the possibilityof the valve member sticking in the closed position or being damaged byspalling, etc.

While only a single embodiment of a preferred form of the invention isillustrated and described the invention is not considered limited to theprecise construction disclosed. Various adaptations, modifications anduses of the invention will be apparent to those skilled in the art towhich the invention relates and the intention is to cover all suchadaptations, modifications and uses which come within the scope orspirit of the appended claims.

What is claimed is:
 1. An engine coolant flow control valvecomprising:(a) a tubular valve housing defining a coolant flow passageextending therethrough; (b) a butterfly valve member supported in saidvalve body for pivotal movement between an open position wherein coolantflows through said body and a closed position wherein coolant flow isblocked, said valve member defining a periphery sealingly engageablewith the valve housing when in said closed position, said valve memberand said valve body engaging resiliently when said valve member is inthe closed position; (c) a valve actuator comprising an actuator housingand a fluid pressure actuated member supported for movement in saidactuator housing; (d) a structural support housing interconnecting saidactuator housing and said valve housing for preventing relative movementtherebetween; (e) an actuating force transmitting linkage connectedbetween said pressure actuated member and said valve member for movingsaid valve member between said positions; and, (f) a force limitingmeans comprising an abutment element carried by said linkage andengageable with one of said housings to limit the force applied to saidvalve member from said actuator when said valve member is in said closedposition, said abutment element located on said linkage relative to saidone housing for engaging said one housing after said valve member andsaid valve housing are resiliently engaged to limit the resilientengagement to a predetermined degree.
 2. The valve claimed in claim 1wherein said abutment element is formed integrally with said linkage andprojects thereform, said abutment element including a projecting portionengageable with said one of said housings.
 3. The valve claimed in claim1 wherein said linkage comprises a shaft-like member drivingly connectedto said valve member, a crank member drivingly connected to saidshaft-like member and a link member extending between said fluidpressure actuated member and said crank member, said abutment elementcarried by said link member so that the force transmitted by the drivingconnections is limited by engagement of said abutment element and saidone housing.